1. Field of the Invention
This invention relates generally to evaporative cooler structures and more particularly to an improved cooler pad assembly for use in such structures.
2. Description of the Prior Art
As is well known in the art, an evaporative cooler is an apparatus which is used primarily in warm arid climates for producing relatively low cost cooled air by utilization of the evaporation principle. Evaporative coolers include a cabinet-like housing having at least one cooler pad assembly demountably mounted in the side thereof. An air moving mechanism such as a fan or centrifugal blower is mounted in the housing and is operated to draw warm ambient air into the interior of the housing through the cooler pad assembly and direct the air to a point of use such as into a building. The evaporative cooler further includes a water containment and handling system for continuously circulating water through the cooler pad assembly to keep it wet and thereby cool the incoming air as it moves through the cooler pad into the housing.
The most commonly used type of cooler pad assembly includes a substantially rectangular frame structure which is formed of sheet metal and is configured to demountably contain a wettable pad medium that is held in place by means of an open wire rod grill.
The sheet metal frame structure is formed with an air inlet face in which a plurality of louvered openings are stamped or otherwise formed. An opposed pair of channel-shaped side members, a channel-shaped bottom member and a top water distribution trough coextend normally from the inner surface of the louvered face and cooperate therewith to define a chamber for containment of the wettable pad medium. The chamber provided by the frame structure has its outwardly facing planar surface defined by the louvered air inlet face and its opposite, or inwardly facing, planar surface is open and is surrounded by flanges formed integrally on the side and bottom frame members and on the water distribution trough of the frame structure.
The wettable pad medium may be formed of any suitable porous wettable medium with the most commonly used pad being formed of excelsior. An excelsior pad is formed into a rectangular pad which closely matches the interior configuration of the chamber defined by the frame structure by loosely packing the excelsior in a cheese cloth like wrapper. Such a pad is placed in the chamber of the frame structure through the open back and the wire rod grill is used to demountably hold the pad in the frame structure.
A first type of wire grill, which has been used for many years, is formed of relatively stiff small gage wire rods which are arranged in a crossed array in the manner of a checker board and are welded to form a grid-like network of vertical and horizontal rod, each having freely extending opposed ends. The open grid-like network, or grill, additionally has a plurality of normally extending prongs coextend from one surface thereof in spaced apart increments.
When the wettable pad is placed in the chamber of the frame structure, the wire rod grill is placed on the pad so that the prongs extend into the pad and hold it in place during use. The freely extending opposite ends of the horizontal and vertical rods of the grill are then placed under the flanges which define the back opening of the frame's chamber to hold the grill, and thus the pad, in place. Placing the ends of the rods under the flanges is difficult in that it usually involves simultaneous bending of the rods, deflecting of the flanges and pushing inwardly on the resilient pad medium to accomplish the installation. And, the same bending, deflection compressing of resilient pad medium must be accomplished when the time comes to replace the pad with a new one. Such replacement is recommended at least once during a season of evaporative cooler use, and preferably twice, due to the dirt and deposited mineral build-up in the pads. Replacement of the pad medium is often much more difficult than installation of a new one due to the above mentioned pad contamination which severely reduces its compressability and resiliency and due to rust and mineral deposition in the area where the wire rod grill is in engagement with the frame structure.
In any case, installation and replacement of the new wettable pad medium is difficult for some people to accomplish due to the difficulty encountered in installing and removing the wire grill. And, almost invariably, the rods of the grill and the flanges become bent and otherwise deformed.
In an effort to ease these installation replacement problems and reduce the above described structural damage, a relatively new type of wire rod grill has been devised. This prior art grill is formed in plural grill segments, two or three depending on pad size, and those segments are installed so that they extend across the pad assembly between the opposed side frame members of the frame structure. Each of the grill segments includes a spaced apart pair of longitudinally extending rods which are interconnected by U-shaped cross rods which, in addition to accomplishing the interconnecting function and also provide the needed pad engaging prongs. The aligned free ends of the longitudinal rods of each grill segment are bent into hook-shaped configurations on both ends thereof and the hook ends are inserted from the pad side through holes formed in the flanges of the side frame members to keep the grill segments from moving down in the frame. This second prior art grill structure, instead of easing the installation and removal problems, made it more difficult to install and virtually impossible to remove the grill structure. installation is difficult due to the need for engaging the hooked ends of the grill segments in the holes provided in both of the side frame members of the frame structure while simultaneously bending the grill segments, deflecting the flanges and compressing the pad medium. Grill segment removal is extremely difficult in that the pad medium becomes so hard that it cannot be compressed enough to allow disengagement of the hooks. This, along with corrosion and mineral deposits in the areas of the hooks makes it necessary in most, if not all, cases to cut the grill segments to accomplish the required removal.
Therefore, a need exists for a new and improved evaporative cooler pad assembly which overcomes some of the problems and shortcomings of the prior art.